Re: [PATCH] x86: add more x86-64 micro-architecture levels
From: John
Date: Sun Sep 15 2024 - 14:43:26 EST
On Sunday, September 15th, 2024 at 7:40 AM, Dave Hansen <dave.hansen@xxxxxxxxx> wrote:
> In the WORST case, we shouldn't be doing this with bools. Do this:
>
> config X86_MARCH_VER
> int "Compiler Micro-Architecture Level"
> range 2 4
> depends on (CC_IS_GCC && GCC_VERSION > 110000) ||
>
> (CC_IS_CLANG && CLANG_VERSION >= 120000)
>
> depends on EXPERT
> depends on X86_64
> help
> Specify a specific compiler "micro-architecture" version.
> You might want to do this when...
> You can find the best version for your CPU here...
> The pitfalls of this option are...
>
> Then you can do fun like:
>
> config X86_L1_CACHE_SHIFT
> int
> default "7" if MPENTIUM4 || MPSC
> + default "6" if MK7 || MK8 || MPENTIUMM || MCORE2 || ...
> + X86_MARCH_VER >= 2
>
>
> which has the added advantage of never needing to be touched when v5
> gets added.
I like this approach much better, it is more streamlined and clean. I ran with your suggestions and the attached seems to work. I am grateful for my feedback and suggestions on the syntax.
---
arch/x86/Kconfig.cpu | 27 +++++++++++++++++++--------
arch/x86/Makefile | 9 +++++++--
2 files changed, 26 insertions(+), 10 deletions(-)
diff --git a/arch/x86/Kconfig.cpu b/arch/x86/Kconfig.cpu
index 2a7279d80460..2b24574f6ac5 100644
--- a/arch/x86/Kconfig.cpu
+++ b/arch/x86/Kconfig.cpu
@@ -308,6 +308,17 @@ config X86_GENERIC
This is really intended for distributors who need more
generic optimizations.
+config X86_MARCH_VER
+ int "Compiler Micro-Architecture Level"
+ range 1 4
+ depends on (CC_IS_GCC && GCC_VERSION > 110000) || (CC_IS_CLANG && CLANG_VERSION >= 120000)
+ depends on X86_64
+ help
+ Specify a specific compiler "micro-architecture" version.
+ You might want to do this when...
+ You can find the best version for your CPU here...
+ The pitfalls of this option are...
+
#
# Define implied options from the CPU selection here
config X86_INTERNODE_CACHE_SHIFT
@@ -318,7 +329,7 @@ config X86_INTERNODE_CACHE_SHIFT
config X86_L1_CACHE_SHIFT
int
default "7" if MPENTIUM4 || MPSC
- default "6" if MK7 || MK8 || MPENTIUMM || MCORE2 || MATOM || MVIAC7 || X86_GENERIC || GENERIC_CPU
+ default "6" if MK7 || MK8 || MPENTIUMM || MCORE2 || MATOM || MVIAC7 || X86_GENERIC || GENERIC_CPU || X86_MARCH_VER >= 2
default "4" if MELAN || M486SX || M486 || MGEODEGX1
default "5" if MWINCHIP3D || MWINCHIPC6 || MCRUSOE || MEFFICEON || MCYRIXIII || MK6 || MPENTIUMIII || MPENTIUMII || M686 || M586MMX || M586TSC || M586 || MVIAC3_2 || MGEODE_LX
@@ -336,11 +347,11 @@ config X86_ALIGNMENT_16
config X86_INTEL_USERCOPY
def_bool y
- depends on MPENTIUM4 || MPENTIUMM || MPENTIUMIII || MPENTIUMII || M586MMX || X86_GENERIC || MK8 || MK7 || MEFFICEON || MCORE2
+ depends on MPENTIUM4 || MPENTIUMM || MPENTIUMIII || MPENTIUMII || M586MMX || X86_GENERIC || MK8 || MK7 || MEFFICEON || MCORE2 || X86_MARCH_VER >= 2
config X86_USE_PPRO_CHECKSUM
def_bool y
- depends on MWINCHIP3D || MWINCHIPC6 || MCYRIXIII || MK7 || MK6 || MPENTIUM4 || MPENTIUMM || MPENTIUMIII || MPENTIUMII || M686 || MK8 || MVIAC3_2 || MVIAC7 || MEFFICEON || MGEODE_LX || MCORE2 || MATOM
+ depends on MWINCHIP3D || MWINCHIPC6 || MCYRIXIII || MK7 || MK6 || MPENTIUM4 || MPENTIUMM || MPENTIUMIII || MPENTIUMII || M686 || MK8 || MVIAC3_2 || MVIAC7 || MEFFICEON || MGEODE_LX || MCORE2 || MATOM || X86_MARCH_VER >= 2
#
# P6_NOPs are a relatively minor optimization that require a family >=
@@ -356,15 +367,15 @@ config X86_USE_PPRO_CHECKSUM
config X86_P6_NOP
def_bool y
depends on X86_64
- depends on (MCORE2 || MPENTIUM4 || MPSC)
+ depends on (MCORE2 || MPENTIUM4 || MPSC || X86_MARCH_VER >= 2)
config X86_TSC
def_bool y
- depends on (MWINCHIP3D || MCRUSOE || MEFFICEON || MCYRIXIII || MK7 || MK6 || MPENTIUM4 || MPENTIUMM || MPENTIUMIII || MPENTIUMII || M686 || M586MMX || M586TSC || MK8 || MVIAC3_2 || MVIAC7 || MGEODEGX1 || MGEODE_LX || MCORE2 || MATOM) || X86_64
+ depends on (MWINCHIP3D || MCRUSOE || MEFFICEON || MCYRIXIII || MK7 || MK6 || MPENTIUM4 || MPENTIUMM || MPENTIUMIII || MPENTIUMII || M686 || M586MMX || M586TSC || MK8 || MVIAC3_2 || MVIAC7 || MGEODEGX1 || MGEODE_LX || MCORE2 || MATOM || X86_MARCH_VER >= 2) || X86_64
config X86_HAVE_PAE
def_bool y
- depends on MCRUSOE || MEFFICEON || MCYRIXIII || MPENTIUM4 || MPENTIUMM || MPENTIUMIII || MPENTIUMII || M686 || MK8 || MVIAC7 || MCORE2 || MATOM || X86_64
+ depends on MCRUSOE || MEFFICEON || MCYRIXIII || MPENTIUM4 || MPENTIUMM || MPENTIUMIII || MPENTIUMII || M686 || MK8 || MVIAC7 || MCORE2 || MATOM || X86_64 || X86_MARCH_VER >= 2
config X86_CMPXCHG64
def_bool y
@@ -374,12 +385,12 @@ config X86_CMPXCHG64
# generates cmov.
config X86_CMOV
def_bool y
- depends on (MK8 || MK7 || MCORE2 || MPENTIUM4 || MPENTIUMM || MPENTIUMIII || MPENTIUMII || M686 || MVIAC3_2 || MVIAC7 || MCRUSOE || MEFFICEON || X86_64 || MATOM || MGEODE_LX)
+ depends on (MK8 || MK7 || MCORE2 || MPENTIUM4 || MPENTIUMM || MPENTIUMIII || MPENTIUMII || M686 || MVIAC3_2 || MVIAC7 || MCRUSOE || MEFFICEON || X86_64 || MATOM || MGEODE_LX || X86_MARCH_VER >= 2)
config X86_MINIMUM_CPU_FAMILY
int
default "64" if X86_64
- default "6" if X86_32 && (MPENTIUM4 || MPENTIUMM || MPENTIUMIII || MPENTIUMII || M686 || MVIAC3_2 || MVIAC7 || MEFFICEON || MATOM || MCORE2 || MK7 || MK8)
+ default "6" if X86_32 && (MPENTIUM4 || MPENTIUMM || MPENTIUMIII || MPENTIUMII || M686 || MVIAC3_2 || MVIAC7 || MEFFICEON || MATOM || MCORE2 || MK7 || MK8 || X86_MARCH_VER >= 2)
default "5" if X86_32 && X86_CMPXCHG64
default "4"
diff --git a/arch/x86/Makefile b/arch/x86/Makefile
index 801fd85c3ef6..e2d0d156a919 100644
--- a/arch/x86/Makefile
+++ b/arch/x86/Makefile
@@ -178,14 +178,19 @@ else
cflags-$(CONFIG_MPSC) += -march=nocona
cflags-$(CONFIG_MCORE2) += -march=core2
cflags-$(CONFIG_MATOM) += -march=atom
- cflags-$(CONFIG_GENERIC_CPU) += -mtune=generic
+ ifeq ($(CONFIG_X86_MARCH_VER),1)
+ cflags-$(CONFIG_GENERIC_CPU) += -mtune=generic
+ rustflags-$(CONFIG_GENERIC_CPU) += -Ztune-cpu=generic
+ else
+ cflags-$(CONFIG_GENERIC_CPU) += -march=x86-64-v$(CONFIG_X86_MARCH_VER)
+ rustflags-$(CONFIG_GENERIC_CPU) += -Ztune-cpu=x86-64-v$(CONFIG_X86_MARCH_VER)
+ endif
KBUILD_CFLAGS += $(cflags-y)
rustflags-$(CONFIG_MK8) += -Ctarget-cpu=k8
rustflags-$(CONFIG_MPSC) += -Ctarget-cpu=nocona
rustflags-$(CONFIG_MCORE2) += -Ctarget-cpu=core2
rustflags-$(CONFIG_MATOM) += -Ctarget-cpu=atom
- rustflags-$(CONFIG_GENERIC_CPU) += -Ztune-cpu=generic
KBUILD_RUSTFLAGS += $(rustflags-y)
KBUILD_CFLAGS += -mno-red-zone
--
2.46.1